1. Field of the Invention
The present invention relates to a ring combustion chamber with ring burner for gas turbines.
2. Description of the Prior Art
Compared to individual combustion chambers, ring combustion chambers have, among other things, the advantage of a more compact gas turbine construction. However, the pressure loss caused by a conventionally constructed ring combustion chamber is more often greater than that of an individual combustion chamber. Moreover, both share the common characteristic of unsatisfactory pre-turbine temperature distribution.
Today's common burners for ring combustion chambers consist of a relatively small number of individual burners distributed around the circumference of the ring combustion chamber, generally 10 to 20 burners but up to 48 in exceptional instances. Thus, the temperature distribution in the gas stream when entering the turbine is not as uniform as is desired, particularly with a small number of individual burners. Moreover, with these burners a large recirculation zone is needed for satisfactory flame stabilization. Such a zone is produced with twist generators (twisters) or flame retention baffles which exacerbate the pressure loss in the combustion chamber.
A further disadvantage for such conventional burners is that, at least in the ignition zone of the fuel/air mixture, stoichiometric conditions exist and thus locally high flame temperatures which encourage the formation of nitrogen monoxides. Thus, the total air flow through the burner is, with the exception of the cooling air stream, divided into a primary air stream flowing through the combustion zone and one or more air mix streams which must be well mixed and swirled with the combustion gases after leaving the burner exhaust. This calls for high speeds with correspondingly large pressure losses.